Variable light source

ABSTRACT

A light source includes features configured to compensate for discontinuous solid state sources. The light source can produce a wide color gamut in display, and improved color rendering of tissue under observation by phosphor gap filling with colored LEDs. The light source can include provisions to depart from a white light spectrum to heighten differences in anatomical features or functions. The light source can include provisions to introduce narrow-band solid-state sources for producing false-color and pseudo-color images, with variable color rendering to change the power spectral distribution and to compensate for fiber optic length and fiber optic diameter tip sensing.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 15/973,433 filed May 7, 2018, which claims thebenefit of priority to U.S. Provisional Appl. No. 62/503,262 filed May8, 2017 and to U.S. Provisional Appl. No. 62/517,089 filed Jun. 8, 2017.The above applications are incorporated in their entireties by referenceherein.

BACKGROUND Field

This disclosure relates generally to light sources such as for surgicalvisualization. This light source may be adjustable so as to provide thedesired illumination. The light source may comprise one or moresolid-state light sources such as LEDs and/or laser diodes, which maypotentially be coupled to fiber optics in some cases.

Description of the Related Art

Surgical visualization systems can assist healthcare providers visualizea surgical site during surgery. Such surgical visualization systems mayinclude one or more types of cameras. Illumination can also be providedto the surgical site to enhance viewing and to assist in thevisualization of surgical sites. Additionally, the spectral distributionof such illumination may be suitably tuned to enhance visualization.Such illumination may potentially be varied in different circumstances.Visualization systems may include cameras including but not limited tocameras that provide surgical microscope views, endoscopes, cameras onretractors, cameras on surgical tools, proximal cameras, exoscopes, etc.The visualization systems may include binocular displays that mayinclude one or more displays (e.g., monitors) and may be configured toprovide 2D or 3D viewing.

SUMMARY

Various examples described herein include light sources that can providelight that is directed to a surgical site. The light source can be avariable light source that can be adjusted to provide different spectraldistributions. The light source can therefore be tuned to provide thedesired type of lighting.

The light source may include one or more solid state emitters such asLight Emitting Diodes (LEDs) and/or lasers (e.g., laser diodes). TheseLEDs may be white LEDs and/or color LED's such as red green and blueLEDs. Other colors LEDs as well as other types of light sources may beemployed. The light from the light sources can be combined to provide anaggregate beam that is used to illuminate the surgical site.

Light from the one or more light sources and be tuned with a tunablefilter that tailors the spectral distribution. Such tunable filters maycomprise a filter such as an interference filter that is tilted to alterthe spectral characteristics of the filter.

Light from the various emitters may be passed through different tunablefilters to control the spectral distribution of the contributions oflight from the different emitters. In this manner, the aggregate beamthat is directed onto the surgical site may be tailored to provide thedesired spectral characteristics.

Optical fiber may be employed at some stage to deliver the light to thesurgical site. For example, the light from the emitters, tuned by thetunable filters and combined may be coupled into fiber optics. Lightpropagated through the fiber optics maybe directed onto the surgicalsite.

Accordingly, certain examples described herein include efficient,high-intensity, solid-state light sources such as LEDs and/or laserdiodes that provide light that is spectrally tuned and collected anddirected possibly into optical fiber or other optics that collects thelight. Example designs may thus provide variable light rendering usingsmall high-intensity light sources that propagate light through acollection of pathways for illuminating the receiving end of a fiberoptics illumination conduit or light conduit. More particularly, certainembodiments may provide variable light rendering using smallhigh-intensity light sources that output light that is directed to oneor more variable filters via a collection of pathways for illuminatingone end of a fiber optics illumination conduit or light conduit. Certainexamples combine phosphor-coated LED high-intensity light sources andcolored light sources (e.g., laser diodes) for excitation via acollection of pathways for illuminating one end of a fiber opticsillumination conduit or light conduit.

Various designs may be configured to provide the user with choices forthe illumination modes. The light source, for example, may be adjustedby the user to provide different types of illumination having differentspectral make-up. The optical spectrum of the light provided may, forexample, be adjusted by controlling which light sources is used toprovide light as well as possibly by tuning light from the one or morelight sources using the tunable filters.

Various designs may include a communication system to receiveinstructions from the user to control the illumination mode and/or tocontrol the spectral distribution of the light output by the lightsource. A communication system may also provide communication to one ormore displays and/or one or more cameras.

Various designs include an illumination device comprising at least onesub-source comprising a plurality of light emitters configured toproduce light flux. The illumination device further comprises aplurality of optical fibers, each optical fiber of the plurality ofoptical fibers comprising a first end portion configured to receive thelight flux from a corresponding light emitter and a second end portionconfigured to emit the received light flux. The light emitters arearranged in a first pattern, the first end portions are arranged in thefirst pattern, and the second end portions are arranged in a secondpattern different from the first pattern.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic diagram of an example spectral filter such as abandpass interference filter comprising a plurality of layers disposedon a substrate.

FIG. 1B is a schematic illustration of a plot of the opticaltransmission versus wavelength (both in arbitrary units) for the filterof FIG. 1A showing a peak in optical transmission.

FIG. 1C is a schematic diagram of the spectral filter of FIG. 1A tiltedclockwise.

FIG. 1D is a schematic illustration of a plot of the opticaltransmission versus wavelength (both in arbitrary units) for the filterof FIG. 1A that is tilted thereby resulting in a shift in the peak inoptical transmission.

FIG. 1E is a schematic diagram of the spectral filter of FIGS. 1A and 1Cfurther tilted.

FIG. 1F is a schematic illustration of a plot of the opticaltransmission versus wavelength (both in arbitrary units) for the filterof FIGS. 1A and 1C that is further tilted thereby resulting in a furthershift in the peak in optical transmission.

FIG. 1G is a schematic diagram of the spectral filter of FIGS. 1A, 1C,and 1E tilted in the opposite direction (counter clockwise) than thetilt (clockwise) shown in FIGS. 1C and 1E.

FIG. 1H schematically illustrates an example color mixing assemblycomprising a plurality of filters in accordance with certain embodimentsdescribed herein.

FIG. 1I schematically illustrates another example color mixing assemblycomprising a plurality of filters in accordance with certain embodimentsdescribed herein.

FIG. 1J schematically illustrates example portions of example colormixing assemblies in accordance with certain embodiments describedherein.

FIG. 2A is a block diagram of an example light source comprising aplurality of LEDs including, e.g., white light LEDs, and color LEDs, aswell as laser diodes.

FIG. 2B schematically illustrates a portion of an example illuminationdevice in accordance with certain embodiments described herein.

FIGS. 3-6 schematically illustrate example illumination modes that canbe offered to the user, for example, via a user interface. Such a userinterface may communicate, for example, with one or more displays andone or more cameras.

FIG. 3 illustrates an example Mode A of the light source of FIG. 2Aconfigured to output an approximation of D65 light.

FIG. 4 illustrates an example Mode B of the light source of FIG. 2Aconfigured to output narrow band illumination.

FIG. 5 illustrates an example Mode C of the light source of FIG. 2Aconfigured to output an approximation of D65 light and near IRexcitation.

FIG. 6 illustrates an example Mode D of the light source of FIG. 2Aconfigured to output D light excitation.

DETAILED DESCRIPTION

Various examples described herein include light sources that can providelight that is directed to a surgical site. These light sources may beused to illuminate a surgical site while one or more cameras captureimages such as video images of the surgical site and may be used fordiagnosis, general medical lighting, or other procedures or activities.Cameras and systems for imaging the surgical site may include, forexample, surgical microscope view cameras, endoscopes, cameras onretractors, cameras on surgical tools, proximal cameras, exoscopes, etc.Such surgical visualization systems may display images such as videousing a binocular display assembly that include displays that provideviews of images obtained from the camera or cameras. The surgicalvisualization systems may switch from viewing an image or video inputfrom one camera to another or show multiple views simultaneously.Moreover, the light source may be automatically varied when switchingfrom displaying a view from one camera to a view from another camera.

Illumination may facilitate enhanced visualization of the surgical sitesuch as obtained by video camera. Light, for example, can be provided tothe surgical site via optical fiber. In some cases where an endoscope isemployed to capture images within the body, the light may be provided tothe surgical site via the endoscope. In certain embodiments, the lightcan be provided via fiber optics in various ways. For example, fiberoptics can be integrated into an endoscope configured to be insertedinto a body via a natural opening or lumen in the body, or through asurgically induced opening in the body. For another example, fiberoptics can be integrated into an exoscope (e.g., an imaging device that“stands off” from the patient and provides a surgery site view) or acamera providing surgical microscope views. For another example, fiberoptics can be brought near the patient to supplement overhead surgicallighting (e.g., used by the physician sans optical devices or withnon-illuminated magnification devices, such as loupes, or to supplementother medical imaging modalities such as endoscopes, exoscopes, orcameras providing surgical microscope views).

The light source can be a variable light source that can be adjusted toprovide different spectral distributions. The light source can thereforebe tuned to provide the desired type of lighting. In particular, it canbe advantageous to provide a light source having a transition (e.g.gradual transition) or a variable change of the output spectral powerdistribution such as a gradual transition or a variable change between awhite light rendering and narrow band imaging.

Certain examples described herein provide such light sources utilizingfilters that have a spectral characteristic that varies with orientationsuch as tilt. Interference filters, for example, have a spectralresponse, such as spectral transmission or refection that varies withangle of orientation. Accordingly, by varying the orientation of thesefilters, the spectral distribution of the light interacting with thefilter can be adjusted or tuned.

In certain embodiments, the light source can operate in three modes, aswell as in combinations of these three modes. The three modes forcertain embodiments can be described as follows:

Mode 1: White light for general medical or surgical illumination (e.g.,“surface” based illumination). This mode can include the ability toilluminate a scene in a D65-near-equivalent matter, and can include theability to modify the color temperature of the “white light” (e.g.,adjusting the wavelength range of the white light to make it warmer orcooler).

Mode 2: Specialized “surface” based illumination (e.g., shortwavelengths; blue waveband; green waveband; D-light; light compatiblewith photodynamic diagnosis (PDD); light which helps visualize changesin the epithelium, in either of two or more sub-modes). For example,this mode can include a sub-mode comprising activating both blue andgreen channels in a manner suitable for narrow band imaging (NBI), andcan include a sub-mode comprising activating only blue light for aD-light mode.

Mode 3: “Deep penetrating” illumination comprising near infrared (NIR)illumination or excitation. This mode can include either or both of twosub-modes: a sub-mode with a broader-based NIR illumination to revealbelow the surface structures in tissue, and a sub-mode with a narrow NIRillumination to excite a dye or other material, which can be used inconjunction with blocking filters.

FIG. 1A schematically illustrates a filter 100 such as an interferencefilter that can be tilted to alter the spectral characteristics of thefilter. The filter 100 comprises a substrate 102 on which a plurality oflayers 104 a, 104 b, 106 a 106 b are disposed. In some designs, aportion of the layers 104 a, 104 b may comprise a first material and aportion of the layers 106 a 106 b may comprise a second material. Asillustrated, the layers 104 a, 104 b, 106 a 106 b may alternate betweenthe first material and the second material. The layers 104 a, 104 b, 106a 106 b may have specific thickness so as to cause optical interferenceof incident light 110 that is reflected from each of the layers thatresults in either constructive or destructive interference and thedesired output. In some designs, filter 100 is designed for a specificwavelength and the layers 104 a, 104 b, 106 a 106 b may have specificthickness, for example, such as a quarter of the wavelength. The layers104 a, 104 b, 106 a 106 b, however, are configured to provide opticalinterference that results in high or low transmission (or reflectivity)for different wavelengths. In this manner, a desired spectralresponsivity maybe designed for the filter 100. For example, thematerials, thickness, and arrangement of the layers 104 a, 104 b, 106 a106 b may be configured to provide a specific spectral characteristicsuch as a pass band. Accordingly, in some examples, the filter 100comprises a band pass filter configured to selectively transmit orreflect a particular wavelength when light 110 is normally incident onthe filter. FIG. 1B, for example, shows a schematic drawing of aspectral distribution 112 for a band pass filter. The band pass filterhas a band pass region 114 where one or more wavelengths of light 110incident on the filter 100 at normal incidence is transmittedtherethrough. This band pass region 114 is show to be centered about thecenter wavelength of λ₀. In contrast, the spectral responsivity 112 ofthe band pass filter has spectral regions above and below the band passregion 114 that provides reduced transmission in comparison to thetransmission of the band pass region for wavelengths above and belowthan the wavelengths of the band pass region.

Changing the orientation of the incident light 110 with respect to thefilter 100 and the interference coating or alternatively changing theorientation of the filter with respect to the incident light can alterthe spectral responsivity 112 of the filter. As illustrated in FIGS. 1Cand 1D, for example, tilting the filter 100 with respect to the incidentlight 110 can shift the band pass region 114. In particular, this bandpass region 100 shifts with tilt. The band pass region 114 for thetilted filter 100 shown in FIG. 1C, is centered about the centerwavelength of λ₁, which is shifted with respect to the center wavelengthof λ₀ of the un-tilted filter.

With further tilt, the spectral responsivity 112 continues to change.Further tilt of the filter 100 of FIGS. 1A and 1C is illustrated inFIGS. 1E and 1F. As shown in FIGS. 1E and 1F, for example, progressivelytilting the filter 100 with respect to the incident light 110 can alterthe band pass region 114 progressively more. In particular, this bandpass region 114 is progressively shifted with tilt. The band pass region114 for the tilted filter 100 shown in FIG. 1E, is centered about thecenter wavelength of λ₂, which is further shifted with respect to thecenter wavelength of λ₀ of the tilted filter of FIGS. 1A and 1 s thusshown as shifted with respect to the center wavelength of λ₁ of thetilted filter of FIG. 1C.

Accordingly, progressively tilting or reorienting the filter 100 withrespect to the incident light can change the transmission or reflectionproperties of the filter and thus changes the spectral distribution oflight transmitted or reflected from the filter. For example, if whitelight is transmitted through the filter 100, a first wavelength band maybe selectively pass through the filter and output therefrom. If thatfilter 100 is tilted slightly, a second wavelength band shifted slightlyin wavelength with respect to the first wavelength band may beselectively passed through the filter and output therefrom. If thatfilter 100 is tilted slightly more, a third wavelength band shiftedslightly more in wavelength with respect to the first wavelength bandmay be selectively passed through the filter and output therefrom.

The interference filter 100 need not be limited to the filter shown inFIGS. 1A-1F. For example, the interference filter 100 need not be a bandpass filter but may for example be a long pass filter or a short passfilter. Additionally, although four layers 104 a, 104 b, 106 a, 106 bare shown, the interference coating may include a larger or smallernumber of layers. Additionally, although two types of layers 104 a, 104b, 106 a, 106 b each comprising a different material are shown,alternately, more than two different types of layers maybe be used. Forexample, the optical coating can comprise three different types oflayers (e.g., a first group comprising a first layer comprising a firstmaterial disposed on a substrate, a second layer comprising a secondmaterial disposed on the first layer, and a third layer comprising athird material disposed on the second layer. This sequence of layers canbe repeated again in a second group comprising another first layercomprising the first material, a second layer comprising the secondmaterial, and a third layer comprising the third material as stackedover the first group of layers. The different materials can havedifferent indices of refraction. One may have a relatively highrefractive index, one a medium refractive index, and one a relativelylow refractive index. Although two groups of layers are described above,the coating may include more groups. Additionally, the groups mayinclude more or less than three layers. Other variations are alsopossible.

FIG. 1G shows the filter 100 as tilted the opposite direction (counterclockwise) than the tilt (clockwise) shown in FIGS. 1D and 1F.

The substrate 102 on which the layers are may comprise glass, plastic,or other materials. In some embodiments the filter 100 is transmissive.Accordingly, the substrate 102 may be transmissive. In other cases, thefilter 100 is reflective. Likewise, although transmission spectra 112are shown in FIGS. 1B, 1D, and 1F, these spectra may be reflectivespectra and the output of the filter 100 may be reflected light that hasa spectral distribution that can be modified in a gradual and continuousmanner by tilting the filter.

Accordingly, actuators such as motors, piezos, etc. may be used to tiltand thereby reorient the filters in a controlled manner with respect tothe incident light. Electrical signals may be applied to the actuators,e.g., motors, piezos, etc., to cause rotation. The electrical signal maybe provided by electronics such as control electronics that controls theamount of tilt of the filter(s) and hence the amount of change ofspectral responsivity of the filter and thus the spectral distributionof the light output (e.g., transmitted through or reflected from) thefilter or filters. In certain embodiments, multiple filters (e.g., ahigh pass filter and a low pass filter) can be placed in a single lightpath. For example, the multiple filters can be stacked on a singlesurface, on opposite sides of a plate or element, and/or coated on asurface or element and embedded within an epoxy bond. The electronicsmay also control the light emitters (e.g., LEDs, laser diodes), forexample, the amount of light output by the light emitter. Suchelectronics, may for example, control the amount of electrical powerthat drives the emitters.

Accordingly, illumination systems may include light sources such as LEDsthat output light that is directed along one or more paths. Tunablefilters such as described above may be included in the one or more pathsto alter the spectrum of the light from the light sources that propagatealong the one or more paths. These paths maybe brought together toprovide an aggregate beam having the desired spectral distribution.

In some examples, therefore, thin film coatings, such as interferencecoatings, applied to one or more plane parallel plates or othersubstrate are placed in the paths of corresponding beams (e.g.,collimated beams) and can be adjustably tilted to vary the color orwaveband distribution.

FIG. 1H schematically illustrates an example color mixing assembly 140comprising a plurality of filters 100 in accordance with certainembodiments described herein. The example color mixing assembly 140 maybe used in the example illumination device schematically illustrated inFIG. 2A and described more fully below. The color mixing assembly 140comprises a first waveguide 150 a (e.g., glass or plastic; mixing rod;light guide or waveguide) having a first output face 152 a, a first lensassembly 160 a, the plurality of filters 100, a second lens assembly 160b, and a second waveguide 150 b (e.g., glass or plastic; mixing rod;light guide or waveguide) having a second output face 152 b and an inputface 154 b. The first output face 152 a is in optical communication withthe first lens assembly 160 a. The first lens assembly 160 a is inoptical communication with the plurality of filters 100, the pluralityof filters 100 is in optical communication with the second lens assembly160 b, and the second lens assembly 160 b is in optical communicationwith the input face 154 b of the second waveguide 150 b. The pluralityof filters 100 is configured to direct the light emitted by theplurality of filters 100 to the second lens assembly 160 b. The secondlens assembly 160 b is configured to focus the light and to couple thelight to the second waveguide 150 b via the input face 154 b of thesecond waveguide 150 b. The second output face 152 b of the secondwaveguide 150 b is configured to direct the light to the fiber opticcables (not shown). For example, the second output face 152 b can be inclose proximity to the fiber optic cables. Light from the opticalemitters is directed to the first waveguide 150 a, propagates throughthe first output face 152 a, through the first lens assembly 160, theplurality of filters 100, the second lens assembly 160 b, and the inputface 154 b of the second waveguide 150 b, with the resultant lightemitted from the second output face 152 b of the second waveguide 150 b.

The first output face 152 a of the first waveguide 150 a is configuredto emit light directed towards the first lens assembly 160 a which isconfigured to substantially collimate the light emitted from the firstoutput face 152 a and to direct the collimated light along the opticalpath 170 through the plurality of filters 100. Each filter 100 of theplurality of filters 100 comprises at least one interference plate 102having at least one dichroic coating applied to at least one face of theplate 102, and the plate 102 is configured to be controllably rotated(e.g., tilted) in at least one direction. The angular and/or rotationaldifferences of the plates 102 are configured to be controllably adjustedsuch that the filters 100 controllably interact with the light receivedfrom the first lens assembly 160 a to modify (e.g., shift; compress) thespectral distribution of the light in an advantageous manner. Forexample, referring to FIGS. 1C and 1D, the spectral distribution of thelight can be shifted and compressed from λ0 to λ1.

The plurality of filters 100 has a center axis 170 along which the lightis propagating from the first lens assembly 160 a to the second lensassembly 160 b in a region between the first lens assembly 160 a and thesecond lens assembly 160 b and the plates 102 of the plurality offilters 100 are located along the center axis 170. The various views ofthe color mixing assembly 140 in FIG. 1H show various example degrees offreedom in which the plates 102 may be configured to be controllablyrotated (e.g., tilted). In view (i) of FIG. 1H, the two plates 102 areboth generally perpendicular to the center axis 170. In view (ii) ofFIG. 1H, one plate 102 is configured to be rotated about an axisperpendicular to the center axis 170 and parallel to the plate 102, andthe other plate 102 is configured to be rotated about an axis parallelto the center axis 170. In view (iii) of FIG. 1H, one plate 102 isconfigured to be rotated about an axis perpendicular to the center axis170 and parallel to the plate 102, and the other plate 102 is configuredto be rotated about an axis perpendicular to the center axis 170 andparallel to the plate 102, with the two rotational axes parallel to oneanother. In view (iv) of FIG. 1H, one plate 102 is configured to berotated about an axis perpendicular to the center axis 170 and parallelto the plate 102, and the other plate 102 is configured to be rotatedabout an axis perpendicular to the center axis 170 and parallel to theplate 102, with the two rotational axes perpendicular to one another.

In various embodiments, the plurality of filters 100 can comprise one ormore dichroic filters. In some embodiments, the plurality of filters 100can comprise one or more polarization components. Rotating or tiltingone or more components of the plurality of filters 100 (e.g., the plate102) about the different rotational axes can induce a spectral change inthe filter output. For example, rotating or tilting one or morecomponents of the plurality of filters 100 (e.g., the plate 102) canattenuate, reduce or extinguish a portion of the signal output from theplurality of filters 100. As another example, rotating or tilting one ormore components of the plurality of filters 100 (e.g., the plate 102)can shift the spectrum of the signal output from the plurality offilters 100.

In various embodiments, the plurality of filters 100 comprising one ormore dichroic filters can be sensitive to polarization of light outputfrom the one or more light sources. In such embodiments, rotating ortilting (e.g., rotating azimuthally) the one or more components of theplurality of filters 100 (e.g., the plate 102) can change the spectralcomposition of the light output from the plurality of filters 100. Forexample, if in a particular orientation of the various components of theplurality of filters 100, the output from the plurality of filters 100can comprise a first amount of light in a first wavelength and a secondamount of light in a second wavelength. When one or more components ofthe plurality of filters 100 is rotated or tilted, the output from theplurality of filters 100 can include different amounts of light in thefirst and the second wavelengths. This effect may result because thefilters may be polarization dependent in some cases. The resultantchange in transmission of different wavelengths through the filter(s)can thus modify the spectral composition of the output of the filters.By increasing and/or decreasing the intensity of different wavelengthsoutput by one or more such filters, for example, the overall shape ofthe spectral distribution can be altered. For example, the magnitude ofcertain spectral wavelengths can be reduced compared to otherwavelengths. Accordingly, various optical emitters can be tailored toemit light having a desired spectral characteristic and/or intensitycharacteristic which when combined with rotation or tilt of the one ormore components of the plurality of filters 100 can provide light withdesired illumination characteristics (e.g., spectral characteristicand/or intensity characteristic).

FIG. 1I schematically illustrates another example color mixing assembly140 comprising a plurality of filters 100 in accordance with certainembodiments described herein. The color mixing assembly 140 shown inFIG. 1I does not include airspaces or lenses through which light istransmitted while propagating through the color mixing assembly 140. Ascompared to the example color mixing assembly 140 of FIG. 1H, theexample color mixing assembly 140 of FIG. 1I replaces the lensassemblies 160 a, 160 b with first and second tapers 180 a, 180 b. Thefirst taper 180 a comprises an input end 182 a in optical communicationwith the output face 152 a of the first waveguide 150 a and an outputend 184 a in optical communication with the plurality of filters 100.The size of the input end 182 a (e.g., diameter; width; area) is smallerthan the size of the output end 184 a (e.g., diameter; width; area) suchthat a numerical aperture of the input end 182 a is smaller than anumerical aperture of the output end 184 a. The second taper 180 bcomprises an input end 182 b in optical communication with the pluralityof filters 100 and an output end 184 b in optical communication with theinput face 154 b of the second waveguide 150 b. The size of the inputend 182 b (e.g., diameter; width; area) is larger than the size of theoutput end 184 b (e.g., diameter; width; area) such that a numericalaperture of the input end 182 b is larger than a numerical aperture ofthe output end 184 b. Thus, the tapers 180 a, 180 b of FIG. 1I serve asimilar function as do the lens assemblies 160 a, 160 b of FIG. 1H.

In certain embodiments, the reduced numerical aperture, or angularoutput, of the color mixing assembly 140 (e.g., whether by lensassemblies 160 a, 160 b of FIG. 1H or by tapers 180 a, 180 b of FIG. 1I)can be used to produce a more collimated flux profile permitting theplurality of filters 100 to be more efficient in modifying (e.g.,shifting; compressing; blocking; passing) portions of the flux energyfrom the optical emitters. FIG. 1I schematically shows a light rayentering the waveguide 150 a at an angle and traversing the length ofthe waveguide 150 a until transitioning into the taper 180 a, where uponthe light ray reflects off a side wall of the taper 180 a at a new angleassociated with the taper 180 a. The sum of the energy of the light rayremains substantially unchanged (e.g., except for small side wall lossesand coupling losses).

The flux energy exiting the plurality of filters 100 is coupled to thewaveguide 150 b by the taper 180 b. As shown in FIG. 1I, the ray pathsof the light propagating through the plurality of filters 100 can besteeply angled relative to the center axis 170 of the plurality offilters 100.

Each of the two plates 102 of the plurality of filters 100 can beconfigured to be controllably rotated (e.g., tilted) with respect to oneanother, thereby permitting modification (e.g., shifting; compressing;blocking; passing) portions of the flux energy propagating through thecolor mixing assembly 140. For example, each of the two plates 102 canbe configured to be controllably rotated (e.g., tilted) about one ormore axes (e.g., the center axis 170 of the plurality of filters 100; anaxis perpendicular to the center axis 170 and parallel to the plate 102;an axis perpendicular to the center axis 170).

FIG. 1J schematically illustrates example portions of example colormixing assemblies 140 in accordance with certain embodiments describedherein. While the waveguides 150, lens assemblies 160, tapers 180, andplates 102 of certain embodiments can be cylindrical and circularlysymmetric, as in view (i) of FIG. 1J, in certain other embodiments, oneor more of the waveguides 150, lens assemblies 160, tapers 180, andplates 102 can include one or more flat sides. Certain such embodimentscan advantageously skew the light rays, mix the flux energy, and/orintegrate the flux energy propagating through the color mixing assembly140 to generate a more even light output. For example, the four-sidedwaveguide 150 shown in view (ii) of FIG. 1J can provide a more evenlight output than can the circularly symmetric waveguide 150 shown inview (i) of FIG. 1J, and the six-sided waveguide 150 (e.g., hex rods)shown in view (iii) of FIG. 1J can provide a more even light output thancan the four-sided waveguide 150. In certain embodiments, the interfacesbetween the larger ends of the tapers 180 with faceted sides can suffermore losses than do interfaces with the circularly symmetric tapers 180,particularly in embodiments in which the plates 102 have circulardiameters. In certain embodiments, an advantageous compromise can beachieved using a six-sided waveguide 150 and a six-sided taper 180. Incertain embodiments, a taper 180 having facets on one end and circularlysymmetric on the other end can be used. In certain embodiments, thetapers 180 and waveguides 150 (e.g., hex rods) of FIGS. 1I and 1J canrotate axially with respect on one another and with respect to thesections containing the plates 102. To facilitate optical couplingbetween the rotating surfaces, a matching index fluid may be disposedbetween the tapers 180 and the sections containing the plates 102. Insome configurations, for example, the light can propagate between thetaper and the index matching fluid and between the index matching fluidand waveguide thereby reducing Fresnel reflection from the surface ofthe taper and the surface of the waveguide as a result of the presenceof index matching fluid. The index matching fluid, may for example havean index of refraction greater than 1.0. The index matching fluid mayhave an index close to the index of the tapers and the waveguides.

The one or more plates (filters) can be coupled to an electricalcontroller configured to simultaneously change the power provided tosome or all of the LEDs in groups or together as the plates are tilted.The light source can also communicate with a control device which maydisplay spectral power distribution to a visualization display. Certainsuch embodiments advantageously provide high power densities usingarrays or assortments of low-cost, high-output LED dies. In certainembodiments, one or more LEDs can be placed in direct contact with oneor more waveguides and can direct their flux energy in the direction ofthe long axis of the waveguide, with the flux energy captured in thewaveguide by total internal reflection.

In certain designs, for example, the illumination system or light sourcemay contain a communication bus, which communicates with one or morecameras. The color responses can vary greatly between cameras, and incertain cases, an input profile can be provided specifically for thecamera. Certain configurations can provide an illumination system thattailors its output for different cameras used in switching the resultantvisualization. The illumination system may, for example, adjust thespectral or color waveband distribution depending on which camera isbeing used to generate the image being viewed by the user.

In certain illumination systems, the variable spectral output generatedusing the tilted plates can be advantageously used with correspondingfilters in the one or more cameras. For example, autofluorescence andexogenous agents utilize intense excitation sources that can obscure theemission of dyes and agents used in many studies. In such circumstances,the camera can include blocking filters to be used in conjunction withthe light source, and the variable output can be adjusted accordingly.For example, the cameras can include filters or detectors that areconfigured to block light below 700 nm, such that autofluorescencelargely disappears in images with wavelengths above 700 nm, sofluorescence imaging in the infrared reduces background “noise” causedby tissue autofluorescence.

Furthermore, color rendering in normal visualization and false-color andpseudo-color rendering can benefit from variable filtering with tiltedplates in some instances. For example, the color rendering in normalvisualization may be more medically useful to the physician if the colortemperature of the light is modified, and/or if the illumination orbrightness level can be varied or modified (e.g., by excluding,enhancing, or otherwise modifying one or more portions of the waveband)by the introduction of one or more variable filters used alone or incombination with one another (e.g., blocking or passing filters). Incertain embodiments, the illumination system is configured to be usedwith a visualization system that incorporates false color and/orpseudo-color images.

As used herein, “false color” refers to a group of color renderingmethods used to display images in color which were recorded in thevisible or non-visible parts of the electromagnetic spectrum, and afalse-color image is an image that depicts an object in colors thatdiffer from those a true-color image would show. A false-color image canbe created using solely the visual spectrum (e.g., to accentuate colordifferences), and/or using data from electromagnetic radiation outsidethe visual spectrum (e.g., infrared, ultraviolet, X-ray), with thechoice of spectral bands governed by the physical properties of theobject under investigation. In addition, variants of false color (e.g.,pseudo-color, density slicing, and choropleths) can be used forinformation visualization of either data gathered by a single grayscalechannel or data not depicting parts of the electromagnetic spectrum(e.g., elevation in relief maps or tissue types in magnetic resonanceimaging). In contrast to a true-color image, a false-color imagesacrifices natural color rendition in order to ease the detection offeatures that are not readily discernible otherwise (e.g., the use ofnear infrared for detecting emission from an exogeneous dye; imagingtissue features hidden below the surface which are visible in the nearinfrared, but not visible in visible light, such as in a range of 400nm-700 nm).

In certain designs, the illumination device can include one or moretilting planes and a mix of phosphor-converted LEDs (e.g., white LEDs;blue or purple LEDs coated with a phosphor to reemit over a broader andlonger wave band range), multi-colored LEDs (e.g., a plurality of LEDsof two or more different colors), and/or one or more other excitationsources (e.g., near-IR). For example, in photodynamic therapyapplications, which utilize illumination in the UV and blue regions(e.g., soret band range), suitable excitation sources can be added tothe device and controlled as other modes. Additionally, in otherexamples, near-IR excitation sources can be used with visualillumination or narrow-band imaging (NBI).

FIG. 2A is a block diagram schematically illustrating an example lightsource or illumination device. The example light source or illuminationdevice includes a plurality of sub-source channels or sub-assembliesconfigured to generate light, and a controller subsystem comprising amicro-processor and/or other electronics, a color sensor, a color mixingassembly and one or more filters, and one or more filter motors. Themicro-processor and/or electronics is operatively coupled to theplurality of sub-sources or sub-assemblies configured to generate light,the color sensor, and the one or more filter motors. The output of thecolor mixing assembly and one or more filters may be operatively coupledto fiber optics.

Certain embodiments described herein can utilize one or more colorsensors having a color scheme division of the spectrum. Examples ofcolor scheme divisions include a red-green-blue (RGB) color schemedivision, a cyan-magenta-yellow-black (CMYK) color scheme division, ahue-saturation-value (HSV) color scheme division, or another colorscheme division of the useful spectrum. Each color sensor can have oneor more portions that are responsive to flux from corresponding portionsof the spectrum (e.g., from green or cyan), or one or more portions thatare responsive to one or more corresponding colored LEDs or groupings ofLEDs. The color sensor can be configured to receive a portion of thetotal flux from the at least one optical emitter. For example, a portionof the mixing assembly (e.g., waveguide; mixing rod) can use totalinternal reflection to move flux in a direction from the light source tothe output and a portion of the surface of the mixing assembly cancomprise a dichroic coating which passes one or more wavelengths ofinterest to a color sensor. This portion of the flux can be coupleddirectly to the color sensor (e.g., by contact; via a fiber opticassembly; via a waveguide or mixing rod) to allow the color sensor tosample the flux for its spectral properties. In certain embodiments, theoutput spectrum of the light source can be managed by sampling thesubdivisions of the flux in the waveguide (e.g., mixing rod) and byadjusting the power supplied to one or more of the LEDs (e.g., via themicroprocessor and user interface), for example, to adjust the spectralcharacteristics of the light based on the samples obtained using thewavelength specific or color sensors.

In the design shown in FIG. 2A, each sub-source of the plurality ofsub-sources comprises at least one optical emitter (e.g., an LED orlaser diode) and at least one pulse-width modulation (PWM) circuitoperatively coupled to the at least one optical emitter and configuredto respond to control signals from the micro-processor or otherelectronics to drive the at least one optical emitter that is responsiveto signals from the PWM circuit. For example, the output of the LEDs(e.g., in lumens) can be controlled by a PWM circuit generating digitalsignals (e.g., having a number of bits, such as 4 bits, 8 bits, 10 bits,with larger numbers of bits providing finer gradations of intensitylevels) and a serial interface configured to transmit the digitalsignals to the corresponding optical emitters.

FIG. 2B schematically illustrates a portion of an example illuminationdevice in accordance with certain embodiments described herein. Theexample illumination device shown in FIG. 2B comprises at least onesub-source (e.g., one or more pluralities of sub-sources, one or morearrays of sub-sources; one or more sub-source matrices) comprising onelight emitter or a plurality of light emitters (e.g., LEDs) configuredto produce light flux. The example illumination device further comprisesa plurality of optical fibers (e.g., a fiber matrix). The different(e.g. each) optical fibers of the plurality of optical fibers maycomprise a first end portion configured to receive the light flux from acorresponding light emitter or from a plurality of light emitters and asecond end portion configured to emit the received light flux. The oneor more light emitters are arranged in a first pattern. The first endportions may be arranged in the first pattern. and/or the second endportions may be arranged in a second pattern different from the firstpattern.

For example, the at least one sub-source schematically illustrated inFIG. 2B comprises an array of square sub-sources. The light emitters ofthe array of square sub-sources are arranged in a first pattern (e.g.,the array of sub-sources arranged in a rectilinear, square, orrectangular sub-pattern, and the light emitters of different sub-sources(e.g. each sub-source) also arranged in a rectilinear, square, orrectangular sub-pattern). The plurality of first end portions can bearranged in the same first pattern. The plurality of second end portionscan be arranged in a different second pattern (e.g., a circular pattern;a second rectilinear pattern different from the first rectilinearpattern).

The plurality of optical fibers can be mechanically coupled together(e.g., contained in a matrix of adhesive such as epoxy or fused bytemperature) in at least one first end assembly (e.g., at least oneinput receptacle) containing the first end portions and at least onesecond end assembly (e.g., at least one output receptacle) containingthe second end portions. For example, as schematically illustrated byFIG. 2B, the at least one first end assembly can comprise a fiber opticmatrix in a non-round (e.g., square; rectangular) format and the atleast one second end assembly can comprise a sum of fiber optic matricesin a non-square format (e.g., round format). Likewise, the at least onefirst end assembly can comprise a fiber optic matrix in a non-roundformat and the at least one second end assembly can comprise a sum offiber optic matrices in a different non-round format. The number offirst end assemblies can be greater than the number of second endassemblies. For example, the number of first end assemblies can be 4, 9,16, 25, 36, 49, or N² (e.g., each having a square format and configuredto be in optical communication with a 2×2, 3×3, 4×4, 5×5, 6×6, 7×7, orN×N square array of square LEDs, respectively) and the number of secondend assemblies can be 1, 2, 4, 6, 8, or less than N² (e.g., each havinga circular format). Other examples can utilize non-square numbers (e.g.,M×N, with M not equal to N, arranged in a rectangular format or otherformats).

In certain embodiments, a first set of the first end portions can be inoptical communication with the light emitters of a first sub-source anda second set of the first end portions can be in optical communicationwith the light emitters of one or more other sub-sources (e.g., a secondsub-source; a third sub-source; N sub-sources). For example, a first setof the first end portions in a square end assembly and a second set ofthe first end portions in a different square end assembly can receivethe light flux from the respective light emitters, and the second endportions of these optical fibers can be gathered into one or morecircular end assemblies (e.g., to facilitate mixing of the receivedlight flux from the respective light emitters). Such mixing may beaccomplished, for example, by having the relative locations and/or orderof different fibers in the first set of the first end portions bedifferent from the relative locations and/or order of those same fibersin the second set of the first end portions In certain such embodiments,combining the light flux from various sub-sources (e.g., havingdiffering color spectrums, power spectral densities, etc.) at the firstend portions of the first end assemblies to be emitted from the secondend portions of the second end assemblies which may have differentarrangement and/or order, advantageously increases randomization of theflux output.

The plurality of optical fibers can be flexible (e.g., configured to bemoved such that the second end portions are positioned at variousselected locations relative to the first end portions). For example, theflexible plurality of optical fibers can be configured to allow thefirst end portions to be coupled to (e.g., adjacent to) the plurality ofsub-sources (e.g., such that each first end portion is in opticalcommunication with a corresponding one or more of the light emitters ofa sub-source) and the second end portions to be coupled to (e.g.,adjacent to) a filter assembly, lens assembly, mixer assembly, or anassembly combining any combination of filters, lenses and/or mixers(e.g., such that each second end portion is in optical communicationwith a corresponding portion of the filter or lens assembly, asdescribed herein). For example, the individual optical fibers making upthe fiber matrix can each have an outer diameter or lateral dimensionselected to provide a desired flexibility (e.g., an outer diameter orlateral dimension of 20 microns, 30 microns, 50 microns, 70 microns, 80microns, or in any range formed by any of these values). In certainother embodiments, the plurality of optical fibers can be fixed and theat least one sub-source can be configured to move, such that lightemitters of a selected one or more sub-sources of the at least onesub-source are placed in optical communication with at least oneselected set of optical fibers.

In certain embodiments, the sum of the areas of the sub-sources (e.g.,areas of the input square formats) is substantially equal to the area ofthe output (e.g., circular output format) that is in opticalcommunication with the sub-sources. In certain other embodiments, thefirst end portions of the individual optical fibers can be tapered(e.g., such that the numerical aperture of the fiber matrix is greaterthan or less than the input face of the fiber optic matrix).

In some implementations, the plurality of optical fibers could be heatedand drawn producing a taper and/or tapers that could be combinedtogether. In some implementations, the tapers could be different fromone another and combined. The numerical aperture (NA) of a fiber maychange as the area of the fiber changes. According, by tapering a fiberand producing a smaller diameter or cross-sectional area, the numericalaperture at that end can be caused to be increased. Decreasing the areaof the second end portion, for example, may increase the numericalaperture of the second end portion and thus may increase the outputangle or divergence angle of light exiting the optical fiber at thesecond end portion. Alternatively, one could orient the taper the otherway. The first end portion of the fiber may be tapered to produce asmaller diameter or cross-sectional area at the first end compared tothe first end portion. Consequently, the numerical aperture at the firstend portion can be caused to be increased relative to the second endportion. The first end portion can thus accept more light from an LED byusing the smaller end at the source and using the larger end where lightmay be output to focusing, collimating and/or mixing optics. Taperingand reducing the cross-section fiber at the input (e.g., reducing thecross-sectional area at the first end portion compared to the second endportion) can be used to capture more illumination or at the output(e.g., reducing the cross-sectional area at the second end portioncompared to the first end portion) can be used to match the acceptanceangle of an optical system, thereby improving efficiency.

Having different shaped formats for the first and second end assembliescan be useful in some instances to address the shape of structures inwhich emitters are packages. Emitters such as light emitting diodes(LEDs) may be included in square shaped LED sources such as LED arrays.As disclosed herein, a number of small LEDs can be optically coupled toa plurality of fiber matrices having square shape and then transmittedsome distance from the emitters to a surgical device or transmittedinternally within a surgical device. Light from the emitters maypropagate through the fibers to one or more of the second endassemblies, which may be circular in some implementations as discussedherein. In some implementations, the number of second end assembliesincluding the second end portions is less than the number first endportions of fiber, which may be disposed proximal to the emitters. Forexample, one could have a 5×5 array of LED's coupled with one or moresquare fiber matrices and then gather these 25 fibers together into 1,2, 3, 4, etc. circular second assemblies.

Systems, devices, and apparatus disclosed herein may be used todistribute light from one or more first end assemblies into a pluralityof second end assemblies such as circular assemblies. Such systems,devices, and apparatus may be configured to directing light intofocusing optics having a smaller diameter than the aggregate area of theemitters from which light originates. For example, the coupling fiberscan permit coupling the optical power of a large LED or LED array into aplurality (e.g., 2, 3, 4, etc.) of focusing optic assemblies thatindividually have smaller areas than the larger LED or LED array.Similarly, the coupling fibers can permit coupling the optical power ofone or more first end assemblies into a plurality (e.g., 2, 3, 4, etc.)of second end assemblies individually having smaller areas than thetotal cross-sectional area of the one or more first end assemblies.

In certain embodiments, sub-sources (e.g., arrays of sub-sources) can beconfigured to be moved individually or as a group to select at least onesub-source (e.g., at least one array of sub-sources) to be in opticalcommunication with the plurality of first end portions in the at leastone first end receptacle. For example, the sub-sources can be mounted ona support configured to move (e.g., rotate about a hub as the center ofrotation; slide along a track), with the support configured to bepositioned to place at least one sub-source (e.g., an array ofsub-sources) in optical communication with the plurality of first endportions. Different sub-sources on the support can have characteristicsthat are different from the characteristics of the other sub-sources(e.g., one array of sub-sources can comprise light emitters withphosphors to emit white light; another array of sub-sources can compriselight emitters having a different color spectrum, power spectraldensity, etc.). These sub-sources (e.g., arrays of sub-sources) can beat different positions on the support (e.g., four arrays of sub-sourcesat the “12 o'clock,” “3 o'clock,” “6 o'clock,” and “9 o'clock” positionsof a rotating support), and the support can be positioned to place thearray(s) having the desired characteristics (e.g., color spectrum) inoptical communication with the plurality of first end portions. Incertain other embodiments, the plurality of optical fibers can be fixedand the sub-sources (e.g., arrays of sub-sources) can be configured tobe moved as a group to select at least one sub-source (e.g., at leastone array of sub-sources) to be in optical communication with theplurality of first end portions in the at least one first endreceptacle.

In certain embodiments, the portion of the illumination deviceadvantageously allows the packing fraction of the optical fibers to bedimensionally less than the spacing of sub-sources. In some cases, thespacing of illumination devises or emitters can be impacted by thermalmanagement considerations.

In some implementations, the light emitters are generally small and canbe moved while the fiber optic matrix remains stationary and providesthe light flux to additional optical systems or sub-systems (e.g.,collimating assembly, mixing assembly, or focusing lens assembly orcombinations thereof). In certain embodiments, the portion of theillumination device advantageously provides light flux from a square orrectangular array of sub-sources to optical systems or sub-systems thathave different geometries (e.g., systems having a circular aperture orcross-section or field of view and/or that possibly see or transmit animage circle or light bundle).

The illumination device may comprise an illuminator that may be mountedon a stand or attached to different fixtures such as supports. Theillumination device can be brought near the patient possibly tosupplement overhead surgical lighting (e.g., used by the physician sansoptical devices or with non-illuminated magnification devices, such asloupes, or to supplement other medical imaging modalities such asendoscopes, exoscopes, or cameras providing surgical microscope views).In addition or alternatively, the illumination device may be integratedwith other medical imaging devices such as cameras providing surgicalmicroscope views, etc.)

A range of advantages may be obtained using designs and configurationsdisclosed herein. For example, designs disclosed herein may facilitatemixing of light from LEDs that having different color that areselectively activated to provide a desired spectrum. Certain colorlights may be added using selectively activated color emitters (e.g.,LEDs) to supplement an otherwise discontinuous spectrum of whitephosphor LEDs.

Additionally, a plurality of smaller emitters (e.g., LEDs) with gapsbetween them may have less thermal load than a single larger emitter(e.g., LED). Systems, devices, and apparatus disclosed herein may beused to combine light from such a plurality of smaller emitters.Systems, devices, and apparatus disclosed herein may be configured todirect light into smaller diameter focusing optics. Coupling fibers forexample can permit coupling the power of a large LED into four smallerfocusing optics.

A wide range of variations in the illumination device are possible. Forexample, the shapes and arrangements of the array of sub-sources as wellas fiber optic matrix may be different. For example, shapes differentfrom those disclosed for each of the components are possible. Likewiseshapes other than square, rectangular, circular are possible.Additionally, although movement of the emitters has been describedabove, in some implementations the fiber may be moved. For example, thefirst end portions (e.g., the first end assembly) can be moved withrespect to the emitters, sub-sources, and or second end portion in thesecond end assembly. Also, one or both of the first and second endassemblies can merely comprise fused fibers and does not include anyextra components attached to the fibers. Additionally, any systems,devices, components, and/or features described herein can be combinedwith any other systems, devices, components, and/or features describedherein. For example, any systems, devices, components, and/or featuresdescribed in connection with FIG. 2B can be combined with any othersystems, devices, components, and/or features described elsewhereherein, including with respect to any of the other Figures.

In certain embodiments, the at least one PWM circuit can be used tocontrol the optical emitters to provide flicker-free illumination.Time-variant light artifacts (TLAs), commonly called fluctuations orflicker, are noticeable to most humans at frequencies below 70 Hz. Somepeople are sensitive in their central vision region to TLAs withfrequencies up to 100 Hz, while using peripheral vision, TLAs can beperceived with frequencies up to 200 Hz. For wide field of view imagingsystems, it is desirable to manage the illumination to improve (e.g.,optimize) “time variant light quality,” especially since such wide fieldof view imaging systems engage the peripheral vision of the user. Bycomparison, endoscopic images viewed through ocular systems have narrowapparent fields of view (e.g., 10 to 30 degrees). Viewing a medicalimage on a monitoring screen in 2D or 3D (e.g., attached to an arm andsurgical stand) may well engage fields of view of 30 to 45 degrees. Asurgical microscope or electronic near eye display (e.g., fixed on anarm or worn) can have an apparent field of view of 60 to 90 degrees, andimmersive displays (e.g., head mounted or fixed on an arm) can engagenearly the entire periphery of a user's vision system. Thus, in certainembodiments described herein the illumination system utilizes the atleast one PWM circuit to control the generated light to conform to userrequirements for perceptually flicker free illumination (e.g.,substantially above 200 Hz). For example, the at least one PWM circuitcan be configured to control the generated light to direct light ontothe optical emitters at a pulse rate sufficiently fast to avoiddetection of flicker by the user, in one or both of the user's centralviewing region and the user's peripheral viewing region.

In certain embodiments, the at least one PWM circuit can be used tocompensate for differences between the color characteristics ofdifferent medical cameras. For example, single-chip medical cameras andthree-chip medical cameras have different color characteristics due totheir color separation filtering. In some cases, for example,single-chip cameras can use a Bayer filter arrangement with differentcolor filters over different pixels in a repeating pattern, whilethree-chip cameras can use three dichroic filters arranged to producethree different color channels (e.g., a red, green, or blue channel)each with its own sensor array. The pixels in these sensor arrays usedin a three-chip camera have their respective color channels that aresensitive primarily in different respective portion of the spectrum(e.g., red, green, blue, etc.) though there can be spectral orwavelength overlap among the different sensor arrays. The output incolor space of these two families of cameras can produce slightlydifferent responses. Additionally, medical cameras from differentmanufacturers may use different sensor arrays which can add to thedifferences. Using the at least one PWM circuit to compensate fordifferences between different sensor arrays having different spectralcharacteristics or spectral responsivities. For example, using the atleast one PWM circuit to compensate for differences between the colorcharacteristics of these different medical cameras can advantageouslyallow better color matching between single-chip sensors and three-chipsensors and between the products from different camera manufacturers.The modulation circuitry can modulate the at least one light source(e.g. at least one LED) differently for different sensor arrays orcameras.

Various optical emitters can be configured to output illumination havingone or more characteristics (e.g., intensity, wavelength, etc.). Forexample, some optical emitters can be configured to output optical powerthat has a spectral distribution similar to a CIE standard IlluminantD65. The characteristics of the light output from an optical emitter canbe configured to match the detection capabilities of the various camerasthat are configured to view the illumination output from the opticalemitter. The optical emitter can be configured to adjust thecharacteristics of the light output (e.g., using the modulationcircuitry) to more closely match the detection capabilities of thecamera/sensor viewing the illumination output from the optical emitter.For example, the optical emitter can comprise a look up table ofsettings that includes the illumination characteristics that moreclosely match the various cameras/sensors that can view illuminationoutput from the optical emitter. Various cameras/sensors can identifythemselves over a communication link or bus, and the optical emitter canadjust the characteristics of the light output to more closely match thedetection capabilities of the identified cameras/sensors. This featurecan be advantageous when one or more cameras/sensors are switched on oroff or are switched from being used to present images to not being usedto present images or vice versa.

In certain embodiments, the at least one PWM circuit can be used tocontrol the optical emitters to conform to various regulations regardingtheir use. For example, illumination is a time-based quantity, and theproduction of heat in tissue caused by the illumination is also atime-based quantity. For another example, the optical emitters cancomprise one or more laser diodes (e.g., for excitation of an exogeneousdye), in which case the illumination source may potentially be subjectto compliance with various regulatory requirements.

As shown in FIG. 2A, the example illumination device comprises N LEDssub-source channels and a laser diode sub-source channel. One or moreLED sub-source channels and in some cases each LED sub-source channelmay comprise a PWM circuit and a plurality of corresponding LEDsoperatively coupled to the corresponding PWM circuit, and the laserdiode sub-source channel comprises a PWM circuit and one or more laserdiodes operatively coupled to the corresponding PWM circuit. The PWMcircuits are operatively coupled to the power supply. For example, asshown in FIG. 2A, six LED sub-source channels each have a correspondingPWM circuit and a corresponding set of LEDs, with each LED sub-sourcechannel generating light in a corresponding spectrum: WLED(cool/binned), WLED (warm/binned), LED (green/binned), LED(cyan/binned), LED (amber/binned), and LED (dark red/binned). As usedherein, “binned” refers to a collection of optical emitters (e.g., LEDs)with one or more similar properties and that are grouped together. Thebins or groups can be defined by one or more properties including butnot limited to, intensity distribution plots, lumen output, colortemperature, and voltage. For example, a collection of LEDs with similarlumen output, but slightly different color temperatures within the greenrange can be binned together in a LED sub-source channel. Using bins canbe advantageous by widening the peak distribution of the spectral peakof the light generated by the LED sub-source channel (e.g., for LEDshaving individual colors, such as red, green, blue, amber, cyan, etc.,and for white light LEDs). Each of the N LED sub-source channels alsocomprises one or more corresponding color sensors which are operativelycoupled to the power supply and to the output of the correspondingoptical emitters of the channel.

Optical signals outputted from the optical emitters are transmitted to acolor mixing assembly and filters configured to generate light having acorresponding spectrum and to provide this light to the fiber optics.

In the example light source shown in FIG. 2A, in a seventh sub-sourcechannel, a plurality of laser diodes are controlled by digital signalsreceived from a corresponding PWM circuit, and optical signals outputtedfrom the laser diodes are transmitted to the color mixing assembly andfilters. Other numbers and combinations of sub-sources/sub-sourcechannels and emitters are possible. Additionally, the illuminationdevice may include additional components or may exclude one or more ofthe components shown and/or the arrangement of components may bedifferent. Other features may be varied as well.

The light from the outputs of the plurality of sub-sources is directedto the one or more filters inputted into the color mixing assembly. Forexample, the plurality of sub-sources can generate corresponding lightbeams, the light beams can be transmitted through corresponding filtersof the one or more filters to the color mixing assembly. In some cases,the color mixing assembly combines the light beams into a singlecomposite beam. In some cases, the color mixing assembly can comprise atleast one collimator configured to collimate the light beams to a singlecomposite light beam. In certain designs, the light source furthercomprises an optical focusing assembly to converge the composite lightbeam and to transmit the composite light beam to a receiving fiber opticconduit or cable.

The color sensor can be operatively coupled to the outputs of theplurality of sub-sources (e.g., the N LED sources channels; the laserdiode channel) and can be configured to detect and report on thespectral properties of the outputs of the individual sub-sources and onthe overall output to possibly be recorded, controlled, and displayed.Information generated by the color sensor can be provided to themicro-processor, which in response, can transmit control signals to theoptical emitters of the plurality of sub-sources and the one or morefilter motors. For example, the color sensor can comprise one or morepower output sensors configured to detect the output of one or moreoutput channels (e.g., one or more of the N LED sources channels and thelaser diode channel) and can be operatively coupled to themicro-processor or other electronics (e.g., as shown in FIG. 2A) toprovide feedback signals indicative of one or more characteristics ofthe detected light (e.g., output intensity at the excitation peak of thelaser diodes). The micro-processor can be configured to be responsive tothe feedback signals by controlling the one or more output channels. Insome designs, the illumination device or system can be configured toprovide one or more modes the yield illumination having desired spectralcharacteristics. In some cases, the illumination device or systemincludes a user interface through which the user can select between aplurality of such modes.

FIGS. 3-6 schematically illustrate example illumination modes which canbe offered to the user in a user interface which communicates with oneor more displays and one or more cameras.

-   -   FIG. 3 illustrates an example Mode A that provides an        illumination output that approximates CIE illuminant D65, and        that approximates the illumination output of a xenon lamp. In        addition, by adjusting power and filter configurations of the        example light source, different color balances can be achieved.        As illustrated, the illumination system includes blue green        dichroic filters and red dichroic filters that having spectral        characteristics that can be gradually tuned by varying the        orientation of the filter with respect the incident light beams.        In addition to the blue green dichroic filters and red dichroic        filters, a band stop filter can be used to extinguish the red        channel.    -   FIG. 4 illustrates an example Mode B that provides an        illumination output that approximates an illumination output for        narrow-band imaging (NBI). For example, the wavelength range for        NBI can comprise one or more of the following: blue waveband        (e.g., 440 nm-460 nm; range centered at 415 nm and having width        of about 10 nm, 20 nm, or 30 nm; range having width greater than        10 nm, greater than 20 nm, greater than 30 nm, less than 10 nm,        less than 20 nm, less than 30 nm); green waveband (e.g., 540        nm-560 nm; range centered at 540 nm and having width of about 10        nm, 20 nm, or 30 nm; range having width greater than 10 nm,        greater than 20 nm, greater than 30 nm, less than 10 nm, less        than 20 nm, less than 30 nm). In addition, the illumination        output can advantageously be transitioned from visual imaging to        NBI under the user's control. As illustrated, the illumination        system includes blue green dichroic filters and red dichroic        filters that having spectral characteristics that can be        gradually tuned by varying the orientation of the filter with        respect the incident light beams. In addition to the blue green        dichroic filters and red dichroic filters, a band stop filter        can be used to extinguish the red channel.    -   FIG. 5 illustrates an example Mode C which provides an        illumination output which approximates CIE illuminant D65 plus        NIR excitation.    -   FIG. 6 illustrates an example Mode D that provides an        illumination output that approximates a blue light only. For        example, the Mode D light can comprise a narrow band of blue        light (e.g., short wavelength blue light, preferentially        absorbed at the tissue surface; approximately one-half of the        blue waveband component of NBI; 440 nm-450 nm; 450 nm-460 nm).        As another example, the Mode D light can comprise blue        illumination as used in photodynamic diagnosis (PDD) of lesions        (e.g., flat lesions; epithelial lesions; carcinomas), e.g., in        cystoscopy, urology, gynecology, gastroenterology.

In one example, Mode A as shown in FIG. 3 can be selected by the user,and the following example sequence of actions can be performed by theexample light source shown in FIG. 2A:

-   -   Initiate current to a color sensor with driver currents to the        LEDs off, setting the black point (e.g., zero RGB values).    -   Initiate current to an array of warm and cool white LEDs.    -   Use color sensor to measure luminance value Y in beam path        proximal to fiber optic cable at maximum drive current. Dimming        can be a percentage of this value, for example, a lesser value        may be used for maximum to account for lifetime changes, and        Mode B can utilize a driver current that is raised from that of        Mode A.    -   Read value and store.    -   Assign warm LED to red-difference chroma components of the color        space (CR) in color sensor, read and store value.    -   Assign warm LED to blue-difference chroma components of the        color space (CB) in color sensor, read and store value.    -   Compute color values of color space for nominal position        (setting white balance) according to RGB values in matrix to        find white point. Read and store values.    -   Measure RGB values in CIE xyY space. These values can be derived        by integrating the CIE color matching functions with the        measurements of spectral power distribution.    -   Initiate current to an array of colored LEDs (Cyan, Green,        Amber, Deep Red, etc.) (each discrete LED color is given a PWM        channel to control driver current).    -   Remeasure RGB values in CIE xyY space.    -   Compare resulting CIE xy values with D65 in LUT (look up table).    -   Raise or lower colored LED channel driver current to approximate        D65 as stored in LUT.    -   Results in nominal balanced white light configuration, Mode A.    -   Report color sensor values to user interface for display or        storage.

In another example, Mode B as shown in FIG. 4 can be selected by theuser for narrow-band imaging, and the following example sequence ofactions can be performed by the example light source shown in FIG. 2A:

-   -   Use Mode A for starting point.    -   Apply current to red filter motor, which tilts the red dichroic        filter in the warm and cool white LED beam paths, thereby        reducing the red light output. Optionally, an iris diaphragm,        band stop filter, and/or neutral density filter (e.g., a        rotationally variable neutral density filter, variable in steps        or continuously variable) can be used to control the red light        channel originating from white light LEDs, which would utilize a        different physical layout.    -   Simultaneously apply additional current to the warm and cool        white LED PWM driver channels, thereby raising light output in        the remaining blue and green beam paths.    -   Simultaneously apply additional current to the cyan and green        LED PWM driver channels, thereby raising light output in the        blue and green beam paths. In certain embodiments, violet and        blue could be added as well.    -   Initiate current to tilting a blue green trimming filter motor        which tilts the filter in the beam path and sharpens cut-off and        cut-on blue and green wavebands.    -   Optionally, raise or lower current to LEDs drivers to raise or        lower the blue and green output independently. In certain        embodiments, violet and blue could be added as well.    -   Report color sensor values to user interface for display or        storage.

In another example, Mode C (e.g., which can be available as anadditional modality to either Mode A or B), as shown in FIG. 5, can beselected by the user for NIR excitation added to D65-like illuminationof Mode A, and the following example sequence of actions can beperformed by the example light source in FIG. 2A:

-   -   Select in response to the user interface either the NIR laser        diode or the NIR laser diode options.    -   Display warnings for eye safety in display.    -   Apply current to NIR laser diode or select from NIR laser diode        options to initiate.    -   Communicate to the one or more cameras that NIR excitation        energy is to be used and what type (e.g., 700 nm type or 808 nm        ICG type) source is to be initiated. In certain cases, the one        or more cameras will have modes or filters for source type (e.g.        excitation blocking filters).    -   Report output value, in radiant flux or current, and source type        to user interface and display.

In another example, Mode D, as shown in FIG. 6, can be selected by theuser for short blue light for photodynamic therapy (e.g., usingphotosensitizing agent excitation), where the excitation waveband is inthe deep blue and emission in the 625-700 nm range, and the followingexample sequence of actions can be performed by the example light sourcein FIG. 2A:

-   -   Select in response to the user interface either the blue laser        diode or the blue laser diode options (e.g., excitation sources        in the 405 nm range).    -   Display warnings for eye safety in display.    -   Apply current to the blue laser diode or select from the blue        laser diode options to initiate.    -   Communicate to the one or more cameras that the blue excitation        energy is to be used and what type (e.g., 405 nm or Sorel type        with Q range options) source is to be initiated. In certain        cases, the one or more cameras will have modes or filters for        source type (e.g., shutter and timing communication between        illuminator and camera).    -   Report output value, in radiant flux or current, and source type        to user interface and display.

The controller subsystem can be configured to allow the user to chooseone or more modes or combinations of modes, including those shown inFIGS. 3-6 as well as other modes. For example, NIR excitation could beadded to the NBI of Mode B or to Mode D. Likewise, the controllersubsystem can comprise one or more transition filters which may allowthe user to selectively switch among one or more modes, including thoseshown in FIGS. 3-6 as well as other modes. For example, themicro-processor and one or more filters of the controller subsystem canbe configured to allow the user to controllably fade the illuminationoutput from Mode A to Mode D and back.

FIGS. 3-6 also schematically illustrate examples with one or morefilters that can be tuned to gradually change the spectralcharacteristic of the light after interacting with the tunable filter.As discussed above, various filters may comprise one or more stacks of(e.g., dielectric) layers, which may act in a band pass manner byoptical interference, rather than absorption, to shift and/or attenuatethe spectral power distribution. Certain examples described hereinadvantageously allow the light source to illuminate various biologicallyimportant features of the patient by varying the positioning of thefilters through angle space so that the incident angle of light in theilluminator changes with respect to the filter stack. The dielectricstack can be a periodic layering of materials with high index ofrefraction, such as titanium dioxide (n=2.4) or zinc sulfide (n=2.32),and low index materials, such as magnesium fluoride (n=1.38). Thephysical thickness of these material layers can be configured to producea predetermined optical path difference due to the differing indices.Alternately, ordered layers with high, low and medium index materialscan be utilized to both pass desired wavebands and attenuate otherwavebands and/or to shift the central wavelength (CWL) region to shorterwavebands. In certain embodiments, the filters are tilted throughprescribed angles in a collimated beam.

Any systems, devices, components, and/or features described herein canbe combined with any other systems, devices, components, and/or featuresdescribed herein. For example, any systems, devices, components, and/orfeatures described in connection with FIG. 2B can be combined with anyother systems, devices, components, and/or features described elsewhereherein, including with respect to any of the other Figures. Variousexamples of illumination devices and their methods of use are describedherein, such as the examples enumerated below:

Example 1: An illumination device comprising:

-   -   a plurality of sub-sources, each sub-source configured to        generate a light beam;    -   at least one filter configured to controllably adjust a spectral        power distribution of at least one of the light beams generated        by a corresponding at least one sub-source of the plurality of        sub-sources and incident on the at least one filter, the        spectral power distribution controllably adjusted to provide a        gradual transition or a variable change of the spectral power        distribution; and    -   a color mixing assembly configured to receive the light beams        from the at least one filter and to generate a composite light        beam,    -   wherein the at least one filter has a spectral distribution that        is altered when the at least one filter is tilted with respect        to the light beam incident thereon or vice versa.

Example 2: The illumination device of Example 1, wherein at least onesub-source of the plurality of sub-sources comprises at least onesolid-state semiconductor optical emitter producing monochromaticvisible light when an electric current is provided.

Example 3: The illumination device of Example 1 or Example 2, wherein atleast one sub-source of the plurality of sub-sources comprises at leastone solid-state optical emitter containing phosphor and producing awhite light output.

Example 4: The illumination device of any of Examples 1-3, wherein allthe sub-sources comprise at least one colored LED.

Example 5: The illumination device of any of Examples 1-4, wherein allthe sub-sources comprise at least one laser diode.

Example 6: The illumination device of any of Examples 1-5, wherein theat least one filter comprises an interference filter.

Example 7: The illumination device of any of Examples 1-6, wherein theat least one filter comprises at least one plane-parallel plate with oneor both surfaces coated with a thin film coating stack comprising aplurality of layers with different indices of refraction, whereintilting of the plate relative to the light beam transmitted through theplate selectively passes or blocks certain wavelength regions of thelight beam.

Example 8: The illumination device of Example 7, wherein the at leastone plate is positioned in a collimated beam path of the light beam.

Example 9: The illumination device of any of Examples 1-8, wherein atleast one sub-source of the plurality of sub-sources comprises at leastone optical emitter and at least one pulse-width modulation (PWM)circuit configured to control the at least one optical emitter toimprove time variant light quality of the at least one sub-source.

Example 10: The illumination device of any of Examples 1-9, wherein atleast one sub-source of the plurality of sub-sources comprises at leastone optical emitter and at least one pulse-width modulation (PWM)circuit configured to control the at least one optical emitter toconform to user requirements for perceptually flicker free illumination.

Example 11: The illumination device of any of Examples 1-10, wherein atleast one sub-source of the plurality of sub-sources comprises at leastone optical emitter and at least one pulse-width modulation (PWM)circuit configured to control the at least one optical emitter toprovide perceptually flicker free illumination at frequenciessubstantially above 200 Hz.

Example 12: The illumination device of any of Examples 1-11, wherein thecolor mixing assembly comprises a collimator.

Example 13: The illumination device of any of Examples 1-12, furthercomprising an optical focusing assembly to converge the composite lightbeam and to transmit the composite light beam to a receiving fiber opticconduit or cable.

Example 14: The illumination device of any of Examples 1-13, wherein theplurality of sub-sources comprises at least one sub-source comprising aplurality of light emitters configured to produce light flux, theillumination device further comprising a plurality of optical fibers,each optical fiber of the plurality of optical fibers comprising a firstend portion configured to receive the light flux from a correspondinglight emitter and a second end portion configured to emit the receivedlight flux, the light emitters arranged in a first pattern, the firstend portions arranged in the first pattern, and the second end portionsare arranged in a second pattern different from the first pattern.

Example 15: An illumination device comprising:

-   -   at least one sub-source comprising a plurality of light emitters        configured to produce light flux; and    -   a plurality of optical fibers, each optical fiber of the        plurality of optical fibers comprising a first end portion        configured to receive the light flux from a corresponding light        emitter and a second end portion configured to emit the received        light flux, the light emitters arranged in a first pattern, the        first end portions arranged in the first pattern, and the second        end portions are arranged in a second pattern different from the        first pattern

Example 16: The illumination device of Example 14 or Example 15, whereinthe at least one sub-source comprises an array of sub-sources.

Example 17: The illumination device of any of Examples 14-16, whereinthe array of sub-sources is arranged in a rectilinear, square, orrectangular first sub-pattern, the light emitters of each sub-sourcearranged in a rectilinear, square, or rectangular second sub-pattern,the first pattern comprising the first sub-pattern and the secondsub-pattern, and the second end portions are arranged in a circularpattern.

Example 18: The illumination device of any of Examples 14-17, whereinthe plurality of optical fibers are mechanically coupled together in atleast one first end assembly containing the first end portions and atleast one second end assembly containing the second end portions.

Example 19: The illumination device of Example 18, wherein the at leastone first end assembly has a non-round format and the at least onesecond end assembly has a round format or a different non-round format.

Example 20: The illumination device of Example 18, wherein the at leastone first end assembly has a square format and the at least one secondend assembly has a round format.

Example 21: The illumination device of any of Examples 14-20, whereinthe plurality of optical fibers are configured to be moved such that thesecond end portions are positioned at various selected locationsrelative to the first end portions.

Example 22: The illumination device of any of Examples 14-21, whereinthe first end portions are tapered.

Example 23: The illumination device of any of Examples 14-16, whereinthe plurality of optical fibers are mechanically coupled together in aplurality of end assemblies containing the first end portions and onesecond end assembly containing the second end portions.

Example 24: The illumination device of any of Examples 14-16, whereinthe plurality of optical fibers are mechanically coupled together in aplurality of end assemblies containing the first end portions and aplurality of second end assemblies containing the second end portions.

Example 25: The illumination device of any of Examples 14-16, whereinthe first end portions are tapered with respect to the second endportions such that the first end portions are smaller than the secondend portions.

Example 26: The illumination device of any of Examples 14-16, whereinthe second end portions are tapered with respect to the first endportions such that the second end portions are smaller than the firstend portions.

Although described above in connection with particular embodiments, itshould be understood the descriptions of the embodiments areillustrative and are not intended to be limiting. Various modificationsand applications may occur to those skilled in the art without departingfrom the true spirit and scope of the invention.

1.-14. (canceled)
 15. An illumination device comprising: at least onesub-source comprising a plurality of light emitters configured toproduce light flux; and a plurality of optical fibers, each opticalfiber of the plurality of optical fibers comprising a first end portionconfigured to receive the light flux from a corresponding light emitterand a second end portion configured to emit the received light flux, thelight emitters arranged in a first pattern, the first end portionsarranged in the first pattern, and the second end portions are arrangedin a second pattern different from the first pattern.
 16. Theillumination device of claim 15, wherein the at least one sub-sourcecomprises an array of sub-sources.
 17. The illumination device of claim16, wherein the array of sub-sources is arranged in a rectilinear,square, or rectangular first sub-pattern, the light emitters of eachsub-source arranged in a rectilinear, square, or rectangular secondsub-pattern, the first pattern comprising the first sub-pattern and thesecond sub-pattern, and the second end portions are arranged in acircular pattern.
 18. The illumination device of claim 15, wherein theplurality of optical fibers are mechanically coupled together in atleast one first end assembly containing the first end portions and atleast one second end assembly containing the second end portions. 19.The illumination device of claim 18, wherein the at least one first endassembly has a non-round format and the at least one second end assemblyhas a round format or a different non-round format.
 20. The illuminationdevice of claim 18, wherein the at least one first end assembly has asquare format and the at least one second end assembly has a roundformat.
 21. The illumination device of claim 15, wherein the pluralityof optical fibers are configured to be moved such that the second endportions are positioned at various selected locations relative to thefirst end portions.
 22. The illumination device of claim 15, wherein thefirst end portions are tapered.
 23. The illumination device of claim 15,wherein the plurality of optical fibers are mechanically coupledtogether in a plurality of end assemblies containing the first endportions and one second end assembly containing the second end portions.24. The illumination device of claim 15, wherein the plurality ofoptical fibers are mechanically coupled together in a plurality of endassemblies containing the first end portions and a plurality of secondend assemblies containing the second end portions.
 25. The illuminationdevice of claim 15, wherein the first end portions are tapered withrespect to the second end portions such that the first end portions aresmaller than the second end portions.
 26. The illumination device ofclaim 15, wherein the second end portions are tapered with respect tothe first end portions such that the second end portions are smallerthan the first end portions.